Arduino-powered alarm clock

thingiverse

An alarm clock I made a while ago. This serves just for inspiration; the electronics were mostly cobbled together on perfboard; reproducing it might be hard... Powered by an Arduino Nano Pro, an SI4702 FM radio (connected via level shifters), a DS1307 real-time clock and a small audio amplifier. The display is based on four MAX7219 LED matrix moduless from aliexpress. The left- and right hand side of the panel has press-fit holes for 4 small 28mm speakers. The display modules are mounted on an insert, mounted at the front of the clock. On the rightmost module, the 8x8 matrix has been replaced with a daughterboard featuring a 4-digit 7-segment display and some status LEDs. It is slightly offset to compensate for the difference in height. To improve contrast (and reduce brightness), it is mounted behind tinted acrylic glass (my local supplier didn't have acrylic that was very dark, so I ended up using two layers). Top and bottom are mounted to the side panel using self-tapping screws. These might strip out after opening and closing the clock a few times (I ended updating the firmware more often than I'd like to admit); inserting a match into the posts seems to work just fine to provide more grip for the screws. I included the OpenSCAD source. It's not very pretty, and it may not be the best way to acchieve things. The source code can be found at https://github.com/pienjo/ClockRadio